How much riboflavin?
The gut can only absorb a limited amount of riboflavin at one time, and an excess is quickly excreted in the urine. Therefore, No Upper Intake Level for riboflavin has not been established.
=> Light yellow urine = excretion of unused B2. However, riboflavin does not cause any side effects.
No need to take B2 every day.
Every other day for maximal intake. But I take it twice a week when I make a cure with thiamine (B1).
When consumption exceeds the ability to absorb (37 mg), riboflavin passes into the large intestine, where it is catabolized by bacteria to various metabolites that can be detected in feces.[5] There is speculation that unabsorbed riboflavin could affect the large intestine microbiome.[42]
But taking into account that riboflavin is used immediately, thus not stored in the body, excess amounts would be excreted, mainly in the urine (90% in 24H).
The biological half-life of riboflavin in the liver of rats was 6.5 days.
I use Swanson riboflavin 100 mg 2x/wk.
50 mg would be enough if no worrying excipient.
(Here: rice four, gelatin, magnesium stearate). Not every day Mg stearate and not too much.
I didn’t find a better form. But it’s OK for me.
42. https://en.wikipedia.org/wiki/Riboflavin#cite_note-42
